Sandoz Patrick, Jacquot Maxime
Département de Mécanique Appliquée, Institut FEMTO-ST, UMR CNRS, Université de Franche-Comté, Besançon, France.
J Opt Soc Am A Opt Image Sci Vis. 2011 Dec 1;28(12):2494-500. doi: 10.1364/JOSAA.28.002494.
Whereas vision is an efficient way for noncontact sensing of many physical quantities, it assumes a cumbersome imaging system that may be very problematic in confined environments. In such contexts, the design of a compact vision probe can be based on digital holography that is a lensless imaging principle. In this interferometric method, object scenes are reconstructed numerically through wave propagation computations applied to a diffracted optical field recorded as an interferogram. We applied this approach to the visual positioning of a micropatterned glass plate. The pseudoperiodic pattern deposited on the surface is suited for absolute in-plane position determination as well as for fine object-feature interpolation leading to subpixel resolution. Results obtained demonstrate a lateral resolution of 0.1 μm, corresponding to 1/20th of a pixel, from a 150 μm period of the pseudoperiodic pattern and with a demonstrated excursion range of 1.6 cm. In the future, such position encoding could be applied to the backside of standardized sample holders for the easy localization of regions of interest when specimens are transferred from an instrument to another one, for instance in nanotechnology processes.
尽管视觉是一种用于非接触式感知多种物理量的有效方式，但它需要一个笨重的成像系统，而这在受限环境中可能会带来很大问题。在这种情况下，紧凑型视觉探头的设计可以基于数字全息术，这是一种无透镜成像原理。在这种干涉测量方法中，通过对记录为干涉图的衍射光场进行波传播计算，对物体场景进行数值重建。我们将这种方法应用于微图案化玻璃板的视觉定位。沉积在表面的伪周期图案适用于绝对平面内位置确定以及精细的物体特征插值，从而实现亚像素分辨率。所获得的结果表明，从150μm周期的伪周期图案中可实现0.1μm的横向分辨率，相当于一个像素的1/20，并且展示出1.6cm的偏移范围。未来，这种位置编码可应用于标准化样品架的背面，以便在将样品从一台仪器转移到另一台仪器时（例如在纳米技术过程中）轻松定位感兴趣区域。
